Honeycomb panels have been known in a structural material for providing good strength qualities with low mass density. A typical honeycomb structure includes a hexagonally cellular core with a skin layer covering at least one face of the core. The skin is useful, for example, for improving strength and for preventing water ingression.
In some applications, such as for flooring, a honeycomb panel can be expected to receive stress from compressive bending, dropping of objects, and the like. Decking on mobile or fixed bridges is an application which typically involves impact loading plus high bending loads. Applications such as aircraft flooring panels must be extremely lightweight, such as 1 lb./ft..sup.2 (about 5 kg/m.sup.2), yet must tolerate drop impacts. Leading edges of airfoils and other exposed sections of a rapidly moving structure can experience high-impact loads upon collision with small objects.
In a traditional honeycomb configuration, resistance to impact or bending stress damage is achieved by increasing the thickness of the outer skin, increasing the density of the honeycomb, or adding a stringer or hat section to reinforce the outer skin. Water ingression has traditionally been prevented by foam-filling the cells. Each of these methods, however, causes an increase in the mass density of the resulting structure. Accordingly, it would be useful to provide a honeycomb panel which has good strength, particularly for resistance to compressive bending stresses, high resistance to damage from drop and other impacts, and resistance to water ingression while maintaining a low mass density.